I really like my Coralife Super Skimmer. It's the 65 gallon version, and I'm running it HOB on a 26 gallon tank. I've only had a few minor issues, and overall I'm very happy with it. It's going to be put on the sump (HOB) for a 60 gallon tank rack upgrade I'm building right now, too.
Once you figure it out, it works well, IME. I don't agree with Albert's critique, BUT... I don't have any experience with better skimmers.
Here's a good link to help fine-tune these skimmers:
http://www.tylermerrick.com/index.php?page=css_notes
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Kid prilosec